Problem: Khan.scratchpad.disable(); To move up to the maestro level in her piano school, Stephanie needs to master at least $75$ songs. Stephanie has already mastered $39$ songs. If Stephanie can master $4$ songs per month, what is the minimum number of months it will take her to move to the maestro level?
Answer: To solve this, let's set up an expression to show how many songs Stephanie will have mastered after each month. Number of songs mastered $=$ $ $ Months at school $\times$ Songs mastered per month $+$ Songs already mastered Since Stephanie Needs to have at least $75$ songs mastered to move to maestro level, we can set up an inequality to find the number of months needed. Number of songs mastered $\geq 75$ Months at school $\times$ Songs mastered per month $ +$ Songs already mastered $\geq 75$ We are solving for the months spent at school, so let the number of months be represented by the variable $x$ We can now plug in: $x \cdot 4 + 39 \geq 75$ $ x \cdot 4 \geq 75 - 39 $ $ x \cdot 4 \geq 36 $ $x \geq \dfrac{36}{4} = 9$ Stephanie must work for at least 9 months.